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Old 07-14-20, 11:50 PM   #16
NiHaoMike
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Quote:
Originally Posted by AirConditioner View Post
A "future" EV. And that means less room and cargo capacity for thermal mass. Just drop it. You cannot have thermal mass in a vehicle. Jesus...you seem like a smart guy, but you're just talking stupid here. Lithium batteries and fossil fuel make more compact cold storage than anything else...except maybe a bottle of CO2.
For the batteries, a mere 4-5x per pound compared to ice which actually gets reduced to about 2.5x after derating the batteries. Doesn't seem like a huge improvement compared to the cost. On the other hand, you cannot regen into ice storage at any meaningful rate or use it for anything other than cooling, so that's where there's value in batteries.

It's hard to beat the energy per weight of running a generator, but there are a number of obvious disadvantages to that which relegate it to more of a backup application. The real game changer would be fuel cells - quiet and efficient, just needs the cost to come way down.
Quote:
That seems to be an issue I run into a lot. Those cheap little units are SO hard to beat for the parts inside! I've been able to start a 5k BTU from as small as an 800 watt very old modified sine inverter. The compressor makes an odd humming noise on the inverter but I'm sure it would work better with a 2-3kw pure sine wave.

I have heard people claim that when using compressors that were not designed to be mounted on vehicles they die early because they can't handle the vibrations as well. I've seen this as a complaint on RV forums with mini splits. With that said I have no idea what would make an "RV" compressor different, but I know they cost a lot more.

I really like the new DC powered compressors I've seen from China...but, they still seem to cost $500 or more for very very small, incomplete system.

Also if someone is doing something like a van, they're making pure DC mini splits now for direct solar applications in pretty small sizes. Gotta pay to play though.
You can take a look at repurposing a Prius compressor, you'll probably want the Gen3 since that includes the drive circuits.
https://openinverter.org/forum/viewtopic.php?f=14&t=258
There is a disadvantage in that they need about 200V to work, you can either build the battery to run in that voltage range (good idea if you want to be able to regen at high rates without dealing with really high currents) or use a DC/DC converter to get that voltage. It helps that the DC bus in a 120V inverter will be about 180V which probably will work.
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